Telephone instrument



Nov. 3, 1931. s. R. SMITH 1,330,139

TELEPHONE INSTRUMENT Filed Dec. 5, 1929 2 Sheets-Sheen 1 Inventor Sidney Re 11211 Sfifih NOV. 3, 1931. s sum- 1,830,139

. TELEPHONE INSTRUMENT Filed Dec. 5, 1929 2 Sheets-Sheer. 2

--In1 renZczr' Sidney gis nell SETH-L Patented Nov. 3, 1931 UNITED STATES PATENT OFFICE SIDNEY REYNELL SMITH, OF LONDON, ENGLAND, ASSIGNOR TO ASSOCIATED TELEF.

PHONE AND TELEGRAPI-I' COIvTPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF DELAWARE 'rnnmeno'nn INSTRUMENT Application filed December 5, 1929, Serial No. 411,763, and in Great Britain December 7, 1928.

The present invention relates to telephone instruments and is more particularly concerned with the construction of instruments for use in automatic systems for enabling a calling party to complete his connection himself by the transmission of impulses over the line. The invention moreover relates more especially to telephones for use in mines or the like where a particularly solid and robust construction is essential and a dial switch in its usual form is found to be too delicate to meet the arduous conditions of service. The invention, however, also has applications in any situations where the 1 illumination is likely to be poor, since it depends for its operation entirely on a sense of touch, and is independent of the visual perception of any figures or the like indicating how it should be used.

According to the invention the operation of calling a wanted telephone number by the transmission of one or more series of impulses is efiected by means of two keys, one of which is operated a number of times correspondingto the number of impulses in a particular series, while the other key is operated after each series and serves to initiate the actual impulse transmission. This arrangeinent is particularly suitable for mines,

since it has been usual practice for a number of years for the signals controlling the operation of winding to be transmitted'by the operation of a rapper key in a manner somewhat similar to that just described. Moreover, with this arrangement the speed of operation of the key is quite immaterial, though of course the actual speed of impulse transmission is important, andit may be convenient to split the impulses of a series up into groups to facilitate counting, and this clearly will have no deleterious effect since the actual impulse transmission and the separation of one series of impulses from 5 another is definitely controlled by the second llhe invention will be better understood from the following description of one method of carrying it into eifect which should be taken in conjunction with the accompanying drawings. It will be understood, however, that the arrangements shown and described are given by way of example only, and that various modifications of the constructional details can be made without exceeding the scope of the invention.

Referring now to the drawings Fig. 1 shows the portion of the cast iron contain- 111g box which houses the dial operating mechanism shown in side elevation, while Fig. 2 shows'the ratchet and pawl details as viewed through the counting lever side of the box.

Referring now to the construction illustrated in Fig. 1, the dial switch 10 of known type, in which the usual finger hole plate has been replaced by the ratchet wheel 11, is conveniently secured to the angular bracket member 12 by, means of the knurledfinger screws 13. Also the whole assembly so far described is supported on the metal platform 14: which extends between the walls of the cast iron containing box 15, and is fastened thereto by means of the brackets 16 and suitable screws not shown. Extending through the right-hand wall of the containing box 15 and supported on suitable bearings therein are the spindles 17 and 18, carrying at their outside ends the key levers 19 and 20 which are firmlylocked thereto by means of the nuts 21 and 22. In order to afford a ready means of protection, suflicient of the key levers 19 and 20 are enclosed in the rectangular metal housing 23 which is secured to the wall of the containing case 15 by screws or the like, while suitable) rectangular slots out in the upper and lower. faces of the housing permit the keys to be operated therethrough and at the same time limit their movement to the desired amount.

Reference will now be made more particularly to Fig. 2 which shows the ratchet and pawl dial operating mechanism in detail, When the counting lever 19 which is shown dotted is depressed, the associated spindle 17 (Fig. 1) to which it is attached, pivots about its centre thereby carrying with it the L shaped member 24 to which is pivoted the spring controlled pawl 25. As the L-shaped member 24 moves in an upward direction the spring controlled pawl 25 is ca used to ride over the stop 26, so that it comes into engagement with the ratchet wheel 11, thereby causing it to be rotated in a clockwise direction. Moreover, as the L shaped member 24 continues its upward stroke the rounded portion of its shorter arm comes into contact with the cranked arm of the pivoted release link 27, thereby lifting the link against the tension of the hair pin spring 28 until the V-shaped locking catch is raised clear of the spring controlled detent 29 which latter is thereupon forced into engagement with the ratchet wheel 11 under the control of the spring 30. hen key 19 has been depressed to the full extent of its travel, ratchet wheel 11 will have then advanced sufiiciently far to enable detent 29 to drop into position over the end of tooth 31, thereby locking the wheel into position. Consequently when the operator releases the key 19 it returns to its normal position under the influence of the helical spring 32 which is anchored to the mounting platform 14 by means of the slotted stud 33 and is secured to the spindle 17 by the pin 34. It will be appreciated also that as the L shaped member 24 moves to its normal position the release link 27 will continue to be held operated against the tension of spring 28 owing to its V-shaped locking catch riding on the curved arm of the detent 29, also during the return of the L shaped member 24-. to its normal position the lower face of pawl 25 will again come into contact'with the adjustable stop 26. thereby raising the pawl against the tension of spring 35 out of engagement with the ratchet wheel. 11. Hence for every operation of the counting lever 19, the ratchet wheel 11 will be advanced by means of the pawl 25 a further step, each step corresponding to the distance between two consecutive finger holes of the dial. The

maximum number of steps possible with this particular construction it will be noticed is limited to ten, after which the further operation of the counting lever 19 is.without effect since the pawl rides idle on the blank portion 36 of the ratchet wheel 11. hen the required number of impulses have been stored in the manner described, the release lever 20 is then depressed against the tension of spring 38 in order to allow the impulses to be delivered, and the mechanical operations thus involved will now be described.

Upon the operation of the lever 20 the spindle 18 to which it is attached turns about its centre thereby carrying with it the ex tended member 37, the cranked portion of which may be more clearly seen from Fig. 1. As the extension member 37 moves in an up ward direction, its curved portion 39 comes into contact with the pin 40 which is let into the arm of the detent 29, and as the member 37 continues its movement the pin 40 is caused to ride over the curved portion of the member 37 thereby lifting the detent 29 out of engagement with the ratchet wheel 11, and at the same time permitting the V shaped locking catch of the release link 27 to drop into position behind the suitably shaped shoulder of the detent. By this means it will be appreciated that the detent 29 thus locked in its normal position irrespective of the position of the release lever 20, and since the ratchet wheel 11 is now freed, it is returned to normal by a spring under governor control thus effecting the impulse transmission in the usual manner. In order to obviate the possibility of inadvertent impulse registration such as might be caused by the operation of the counting lever when the instrument is not in use, the switch hook is arranged to control the locking detent in the following manner.

Referring again to Fig. 1 it will be seen that the switchhook 4-1 takes the form of .arm 46 which is locked by means of the nut 47 to the spindle 48.

Consequently when the weight of the receiver which .is not shown, is taken by the switchhook 41, the latter is depress-ed against the tension of the spring 49 until it comes to rest against the stop 50, whereby imparting a slight turning movement to the spindle 4L2, which is in turn transmitted via the con- .ecting meinber 4.5 to the lower spindle l; which is pivoted in suitable holes in the angle brackets 12 and 51.

Since the spindle 18 also receives a slight turning movement through the medium of the flat metal connecting members previously explained, it will clearly be seen from reference to Fig. 2 that the trip member 52 whi l 1 is locked thereto will now come into contat with the curved arm of the detent 29, and in case the latter should be in engagement with the ratchetwheel 11 at this instant, the pres sure exerted by the trip member 52 will be sutlicient to restore the detent to its normal position. Hence with this arrangement the operation of the counting lever 19 while the receiver is on the switchhook will produce no effect as regards impulse transmission. since it is impossible to engage the detent 29 with the ratchet wheel. If the dial switch employed is of the type arranged to provide a pause between series of impulses by means of a certain idle movement it may be necessary to effect certain modifications so to cut out this pause, but the manner in which this can be done will be readily apparent to those skilled in the art.

In the present construction the sending of a single series of impulses only is contemplated, and in case it should be necessary to send a plurality of digits it may be desirable to modify the construction so as to lock the counting lever, after the release lever has been depressed, for a time sufiicient to allow the dial mechanism to return to normal, since otherwise interference would result if an attempt were made to send a further digit before the previous one had been completely transmitted.

I claim 1 1. In an impulse transmitting device for telephone systems, a first key and a second key, means responsive to the operation of said first key in accordance with the number of impulses to be transmitted for operating said impulse transmitting device, to prepare it for the transmission of impulses, and means responsive to the operation of said second key for releasing said impulse device to initate the actual transmission of the impulses.

2. In an impulse transmitting device for telephone systems, a manually operable key, means responsive to the operation of said key in accordance with the number of impulses to be transmitted for operating said impulse device to prepare it for the transmission of the impulses, and means for releasing said impulse device to initiate the actual transm1ssion of the impulses, the speed of the transmission of the impulses being independent of the speed of operation of said key.

3. In an impulse transmitting device for telephone substations, a manually operable key, means responsive to the operation of said key for operating said impulse device in accordance with the number of impulses to be transmitted, said key operated once for each impulse, means for'releasing said impulse device for initiating the actual transmission of the impulses, a telephone switchhook associated with said impulse device, and

" an interlocking arrangement between said switchhook and said impulse device for rendering the operation of said key ineffective unless the receiver is removed from the switchhook.

4. In an impulse transmitting device for telephone systems comprising mechanism adapted to be operated and released to trans mit a variable number of impulses, a keyassociated with said mechanism, a ratchet gearing connecting said key with said impulsing mechanism, means responsive to the movement of said key a number of times corresponding to the number of impulses to be transmitted for controlling said ratchet gearing to operate said impulse mechanism to prepare it for the transmission of said impulses, a second key associated with said mechanism, and means controlled by said second key for releasing said impulse mechanism to normal to transmit the impulses.

5. In an impulse transmitting device for telephone systems, a key, a ratchet wheel controlled by said key for operating said impulse devlce, means responsive to'the movement of said key once for each impulse to be transmitted for controlling said ratchet wheel to operate said impulse device and prepare it for the transmission of the impulses,

means on said ratchet wheel for limiting the total number of impulses in a series to be transmitted, and means for releasing said impulse device to normalto transmit 'the impulses.

6. In an impulse transmitting device for telephone systems, a key, a ratchet mechavice in accordance with more than a predeterlTllIlQCl number of nnpulsesm a serles, a sec- 0nd key connected to said ratchet mechanism, and means responsiveto the operation of said second key to release said ratchet wheel to permit said impulse device'to restore to normal and transmit the impulses.

7 In an impulse transmitting device for telephone substations, a key, a ratchet wheel controlled by said keyfor operating said impulse device, means responsive tothe operation of said key once for each impulse to be transmitted for moving said ratchet wheel to operate said impulse device and prepare it for the transmission of the impulses, a second key, means responsive to the operation of said. second key'for releasing said ratchet Wheel to permit said impulse device to restore and transmit the impulses, a telephone switchhook associated with said impulse device, a holding pawl operated by said first key into engagement with said ratchet wheel for holding said ratchet in the position moved by said first key, and means controlled by said switchhook for releasing said holding pawl if the receiver is not removed from the switchhook.

8. In an impulse transmitting device for telephone systems, a key, a ratchet wheel operated by said key for controlling said impulse device to prepare it for the transmission of impulses, said key operated once for each impulse of a series to be transmitted, a holding pawl operated into engagement with said ratchet wheel by said key to hold the ratchet wheel in the position moved by the key. a telephone switchhook associated with said impulse device and controlling said holding pawl, and means controlled by said switchhook when the receiver is on it for preventing said holding pawl from engaging said ratchet wheel.

9. In an' impulse transmitting device for telephone systems, a key, a ratchet wheel operated by said key for controlling said impulse device to prepare it for the transmis- 5 sion of impulses, said key operated once for each impulse of a series to be transmitted, a holding pawl operated into engagement with said ratchet wheel by said key to hold the ratchet wheel in the position moved by the key, a telephone switchhook associated with said impulse device and controlling said holding pawl, means controlled by said switchhook when the receiver is on it for preventing said holding pawl from engaging said ratchet, a second key controlling said holding pawl, and means responsive to the operation of said second key when the receiver is removed from said switchhook for releasing said holding pawl to permit said ratchet wheel to restore to normal and operate said impulse device to transmit the impulses.

10. In an impulse transmitting device for telephone systems, a key, a ratchet wheel operated by said key for controlling said impulse device to prepare it for the transmission of impulses, said key operated once for each impulse of a series to be transmitted a telephone switchhook associated with said impulse device for rendering said ratchet T wheel ineffective to control said impulse device in case the receiver is on the switchhook, a second key associated with said im pulse device for releasing said ratchet wheel, after it has been operated by said first key, to operate said impulse device to transmit the impulses, and a holding pawl for engaging said ratchet wheel controlled by said first key, said switchhook, and said second key.

In testimony whereof I aflix my signature.

SIDNEY REYNELL SMITH. 

